Baselga Cervera, BeatrizGarcía Balboa, María Del CaminoLópez Rodas, VictoriaFernández Díaz, MartaCostas Costas, Eduardo2026-05-052026-05-052019Baselga-Cervera, B., García-Balboa, C., López-Rodas, V., Fernández Díaz, M., & Costas, E. (2019). Evidence of microalgal isotopic fractionation through enrichment of depleted uranium. Scientific Reports, 9(1), 1973. https://doi.org/10.1038/s41598-019-38740-210.1038/s41598-019-38740-2https://hdl.handle.net/20.500.14352/136546Author's Contributions B.B., C.G., V.L. and E.C. conceived the presented idea and the experiments. B.B., C.G., V.L. and E.C. carried out the experiments. M.F. contributed to reagents/materials/analysis tools and samples analyzed. B.B., C.G., V.L., M.F. and E.C. contributed to the interpretation of the results. B.B., M.F. and C.G. wrote the manuscript supervised by V.L. and E.C. B.B., C.G., M.F., V.L. and E.C. made important intellectual contributionsResulting from the nuclear fuel cycle, large amounts of depleted uranium (DU) tails are piling up, waiting for possible use or final disposal. To date, the recovery of the residual 235U isotope contained in DU has been conducted only marginally by physical processes. Relative isotope abundances are often mediated by biological processes, and the biologically driven U isotopic fractionation has been previously identified in reducing bacteria. Our results indicate that the cells of two microalgal strains (freshwater Chlamydomonas sp. (ChlGS) and marine Tetraselmis mediterranea (TmmRU)) took up DU from the exposure solutions, inducing U isotopic fractionation with a preference for the fissile 235U isotope over 238U. The n(235U)/n(238U) isotopic fractionation magnitudes (δ235) were 23.6 ± 12.5‰ and 370.4 ± 103.9‰, respectively. These results open up new perspectives on the re-enrichment of DU tailings, offering a potential biological alternative to obtain reprocessed natural-equivalent uranium. Additionally, the findings present implications for identifying biological signatures in the geologic recordsengAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal article2045-2322https://doi.org/10.1038/s41598-019-38740-2https://doi.org/10.1038/s41598-026-47799-7open access574.5Biología marina2417.05 Biología Marina